1. Field of the Invention
The present invention relates to a magenta toner for electrophotography (hereinafter, sometimes referred to simply as toner) used in machines utilizing an electrophotographic process such as copying machines, printers, facsimiles and the like, particularly, in color copying machines, and a full color image forming method using the same.
2. Description of the Related Art
As the electrophotographic process, a lot of processes including methods described in Japanese Patent No. 42-23910 and the like are conventionally known. In the electrophotographic process, a fixed image is formed via a plurality of steps in which a latent image is formed electrically by various means on a photoreceptor including a photoconductive substance, this latent image is developed using a toner, the toner image on the photoreceptor is transferred onto a recording film such as paper and the like directly or via an intermediate transfer body, and then this transferred image is fixed by heat, press, heat and press, or solvent vapor and the like. Toners remaining on the photoreceptor are removed if necessary by various methods, and the above-mentioned plurality of steps are repeated. Recently, with progress of technologies in the field of electrophotography, such an electrophotographic process is used not only in copying machines and printers but also in printing application, and there are increasingly strict requirements for high image quality and hue of copies equivalent to those of prints, in addition to high speed and high reliability of apparatuses.
In order to attain such requirements, there are various investigations and various suggestions in many aspects such as the melting property of a binder resin, the kind of a colorant, the particle size distribution of a toner, additives and the like. Japanese Patent Application Laid-Open (JP-A) No. 5-142867 suggests a technology in which hue and high reliability are satisfied simultaneously by using a specific pigment. JP-A No. 2000-199982 suggests a technology in which wider hue is reproduced by using a specific toner. JP-A No. 2000-131887 suggests a technology in which high image quality and high reliability are realized by using a toner having specific shape factor SF1 and particle size distribution, and having specific hue. JP-A No. 2001-166541 suggests a technology in which high image quality and high reliability are realized by combining a specific binder resin and a specific colorant.
These technologies can surely reproduce image quality near that by printing, however, this is realized by coated paper having smooth surface and color dedicated paper having enhanced smoothness on the surface for color photography, and in the case of paper having poor surface smoothness such as recycled paper and the like, hue changes and color range narrows in some cases. In particular, when cyan, magenta and yellow toners are used, hue changes easily and color range easily narrows in secondary colors such as red and blue. Recently, regard for environment is strictly required, and use of recycled paper is supposed to further increase, and it is necessary that high image quality is not deteriorated even if paper having poor surface smoothness is used.
On the other hand, JP-A Nos. 11-272014, 2001-249497 and 2001-249497 suggest technologies in which high image quality and high reliability are realized by toners using specific colorants (pigments). However, also in these technologies, since a toner is produced at about 60° C. in a kneading grinding method or wet production, the form of a toner is irregular, and as well as the above-mentioned cases, high image quality and high reliability are realized by coated paper having smooth surface and color dedicated paper having enhanced smoothness on the surface for color photography, and in the case of paper having poor surface smoothness such as recycled paper and the like, hue changes and color range narrows in some cases.